1git-check-ref-format(1) 2======================= 3 4NAME 5---- 6git-check-ref-format - Ensures that a reference name is well formed 7 8SYNOPSIS 9-------- 10[verse] 11'git check-ref-format' <refname> 12'git check-ref-format' --print <refname> 13'git check-ref-format' --branch <branchname-shorthand> 14 15DESCRIPTION 16----------- 17Checks if a given 'refname' is acceptable, and exits with a non-zero 18status if it is not. 19 20A reference is used in git to specify branches and tags. A 21branch head is stored under the `$GIT_DIR/refs/heads` directory, and 22a tag is stored under the `$GIT_DIR/refs/tags` directory. git 23imposes the following rules on how references are named: 24 25. They can include slash `/` for hierarchical (directory) 26 grouping, but no slash-separated component can begin with a 27 dot `.`. 28 29. They must contain at least one `/`. This enforces the presence of a 30 category like `heads/`, `tags/` etc. but the actual names are not 31 restricted. 32 33. They cannot have two consecutive dots `..` anywhere. 34 35. They cannot have ASCII control characters (i.e. bytes whose 36 values are lower than \040, or \177 `DEL`), space, tilde `~`, 37 caret `{caret}`, colon `:`, question-mark `?`, asterisk `*`, 38 or open bracket `[` anywhere. 39 40. They cannot end with a slash `/` nor a dot `.`. 41 42. They cannot end with the sequence `.lock`. 43 44. They cannot contain a sequence `@{`. 45 46- They cannot contain a `\\`. 47 48These rules make it easy for shell script based tools to parse 49reference names, pathname expansion by the shell when a reference name is used 50unquoted (by mistake), and also avoids ambiguities in certain 51reference name expressions (see linkgit:git-rev-parse[1]): 52 53. A double-dot `..` is often used as in `ref1..ref2`, and in some 54 contexts this notation means `{caret}ref1 ref2` (i.e. not in 55 `ref1` and in `ref2`). 56 57. A tilde `~` and caret `{caret}` are used to introduce the postfix 58 'nth parent' and 'peel onion' operation. 59 60. A colon `:` is used as in `srcref:dstref` to mean "use srcref\'s 61 value and store it in dstref" in fetch and push operations. 62 It may also be used to select a specific object such as with 63 'git-cat-file': "git cat-file blob v1.3.3:refs.c". 64 65. at-open-brace `@{` is used as a notation to access a reflog entry. 66 67With the `--print` option, if 'refname' is acceptable, it prints the 68canonicalized name of a hypothetical reference with that name. That is, 69it prints 'refname' with any extra `/` characters removed. 70 71With the `--branch` option, it expands the ``previous branch syntax'' 72`@{-n}`. For example, `@{-1}` is a way to refer the last branch you 73were on. This option should be used by porcelains to accept this 74syntax anywhere a branch name is expected, so they can act as if you 75typed the branch name. 76 77EXAMPLES 78-------- 79 80* Print the name of the previous branch: 81+ 82------------ 83$ git check-ref-format --branch @{-1} 84------------ 85 86* Determine the reference name to use for a new branch: 87+ 88------------ 89$ ref=$(git check-ref-format --print "refs/heads/$newbranch") || 90die "we do not like '$newbranch' as a branch name." 91------------ 92 93GIT 94--- 95Part of the linkgit:git[1] suite